I agree with the poster that asked the question, is the situation temporary and likely to improve, or is it long term? From my personal experience, I was assigned a project a few years ago that was way too much responsibility for that point in my career. My moods were all over the place, from needing to sleep 12 hours a day to waking up at 2 am and driving around town aimlessly. During that period of time I experienced the most euphoric state I have ever felt, and while it felt good in the moment, it was an absolute threat to my stability. I don't know much about disability, but I would think trying to work would be preferable, just for the structure it can bring to your day. I would be really honest with yourself about whether the stress of finding and starting a new job outweighs the stress of your current situation. It is so easy (believe me, because I'm going through it right now) to believe that by changing something major in our lives we will feel better/solve the problem. I would suggest that if there's a way to talk to your boss to lighten your workload it would be helpful.
Best of luck. It's a tough situation.
*hugs*